Self-cleaning drill string tool



May 2, 1967 J. H. M MANUS, JR 3,316,937

SELF-CLEANING DRILL STRING TOOL Filed Dec 10, 1964 2 Sheets-Sheet 1INVENTOR.

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United States Patent 3,316,987 SELF-CLEANING DRILL STRING TOOL James H.McManus, Jr., Box 1994, Lafayette, La. 70501 Filed Dec. 10, 1964, Ser.No. 419,275 19 Claims. (Cl. 175-313) This is a continuation-in-part ofpending application Ser. No. 381,780 filed July 10, 1964. The presentinvention relates generally to well drilling equipment, and morespecifically to certain new and useful improvements in the constructionof drill string tools which are self-cleaning.

Drill string tools such as stabilizers and reamers perform manyfunctions including preventing the drill from spiralling duringdrilling, and insuring that the drill hole does not collapse or contractin diameter and thus prevent removal of the drill.

The main disadvantage of presently known devices of this class is thetendency for the blades of the tool to become clogged, or in theparlance of the field, balled-up. Such a condition is caused byagglomeration of materials such as wall cake and cuttings into a hardball surrounding the blades of the tool. When ball-up is encountered,premature removal of the drill string from the drill hole is required inorder to free or clean the blades. Otherwise,

drilling mud circulation ultimately is blocked by the ball and upwardlyapplied force is exerted on the drill string. This upwardly appliedforce effects a diminution of the predetermined running weight on thedrill bit and, accordingly, a corresponding decrease in drilling rate.Additionally, this upward urging of the drill string causes the bit towalk off the bottom of the hole and often results in a crooked drillhole and, consequently, stuck pipe. Any

decrease in the drilling rate and/or shut downs due to stuck pipeobviously adds materially to the cost of the well.

Further, as the pressure from the drilling fluid builds up below aballed-up tool, the wall formation of the bore hole often is broken downand circulation is lost. In many instances, the drilling tools currentlyavailable have been directly responsible for the added operating expenseof restoring circulation, the costof lost-circulation material and thecost of replacing the mud system.

Accordingly, it is a primary object of this invention to provide a drillstring tool which is self-cleaning.

'Another object of this invention is to provide a drill string toolwhich is capable of removing balled-up material from its surface whileit is in the drill hole.

Still another object of this invention is to provide a drill string toolhaving blades adapted to move axially relative to the drill string andthe bore of the drill hole in'order to overcome problems. presentlyexperienced with tools of this class.

An additional object of this invention is to provide a drill string toolwhich can clean the area between the blades while the drill string is inthe drill hole.

A further object of this invention is to provide a drill string toolwhich can clean the blades of the tool while the drill string is in thedrill hole.

A specific object of this invention is to provide a combinationstabilizer and reamer tool which is self-cleaning,

is ruggedly constructed to perform efficiently and accu-. .rately duringdrilling operations, and which eliminates the balling-up heretoforeencountered with such tools and the problems resulting therefrom.

Additional objects and advantages of this invention will become apparentfrom the following description and In accordance with the presentinvention, it has been found that drill string tools may be madeself-cleaning and thus overcome many of the disadvantages of prior arttools. The self-cleaning is provided by permitting relative longitudinalmovement between the stabilizing and/or 3,316,987 Patented May 2, 1967reaming blades and the tool housing and by incorporating a wiping meanson the tool to remove balled-up material during such relative movement.

Generally described, the present invention is a selfcleaning drillstring tool having in combination a sleeve having means at one end toconnect said sleeve to the drill string, said sleeve having at least oneelongated slot; a mandrel slidably mounted in said sleeve with one endof said mandrel directed out of said sleeve, said one end of saidmandrel having means to connect said mandrel to the drill string; atleast one blade mounted on said mandrel and extending through a portionof an elongated slot in said sleeve and being slidable in the slot; andwiper means mounted on said blade adjacent said sleeve whereby thesliding of said blade in the slot of said sleeve will cause said wipermeans to wipe caked material therefrom.

In accordance with a preferred embodiment of the invention, the sleevehas a plurality of slots spaced about its periphery, the mandrel has acorresponding plurality of blades extending through the slots and thewiper means is an annular band mounted in a slot in each of the blades.It is preferred that the blades be elongated and that one wiper band bemounted at each end of the blades.

In a further embodiment of the invention, the tool is equipped withwiper means such as studs mounted on the sleeve on each side of the slotor slots to wipe caked material from the blades as the bladesreciprocate in the slots. The wiper studs may be used in conjunctionwith the wiper bands or they may be used alone. Preferably both studsand bands are employed.

It is desirable that the slots in the housing be about twice as long asthe blades to allow the wiper means to move substantially along theentire surface of the portion of the sleeve between the blades and toallow the wiper studs to move along substantially the entire sides ofthe blades' If desired, the slots and blades may be helical.

This invention having been generally described, the preferred specificembodiments will be described in detail with reference to theaccompanying drawings.

FIGURE 1 is a plan view of a tool constructed in accordance with theteachings of this invention with the sides partly broken away and incross section so as to reveal the several elements contained therein.

FIGURE 2 is a cross section taken along line 2--2 of FIGURE 1.

FIGURE 3 is a cross FIGURE 1.

FIGURE 4 is a cross section taken along line 4-4 of FIGURE 1.

FIGURE 5 is a perspective view partially in section of another toolconstructed in accordance with the teachings of this inventionillustrating the tool in the retracted position.

FIGURE 6 is a perspective view partially in section of the tool ofFIGURE 5 illustrating the tool in the extended position.

Referring now to the drawings in detail, the numeral 5 represents anelongated cylindrical housing consisting of an upper portion 6 having acylindrical surface 7 of constant diameter. The lower portion 8 is acontinuation of the upper portion but has a slightly reduced diameterforming an outer cylindrical surface indicated at 9. The upper end 10 ofthe housing is formed with .a female tapered thread connector 11 whichcommunicates with a concentric central passage 12 through which drillingmud is pumped as in conventional drilling practice. The central passagecommunicates with an enlarged bore 13 which extends concentricallythrough both the upper and lower portions 6 and 8 of the housing. Thelower portion of the housing is provided with three radial slots 14which are symmetrically positioned and extend longitudinally thereof toterminate at 15 short of the cylinsecti-on taken along line 3-3 ofdrical surface 7. Three guide grooves 16 are machined in the lowerportion 8 intermediate the radial slots 14 and extend beyond the slotsto terminate at 17 within the bore 13 of the upper portion 6. Similargrooves 18 extend along the enlarged bore in the plane of the radialslots 14 beyond their terminating points 15. The lower end 19 of thehousing is provided with a tapered male connecting thread 20 whichreceives a split nut 21, the nut being ultimately welded in positionafter assembly. A small split bearing ring 22 is received in the lowerend of the enlarged bore 13 and is maintained therein by the flanges 23of the split nut 21.

The second major component of this tool comprises a mandrel 24. Themandrel has a lower portion 25 of cylindrical section equal to that ofthe housing 5. The end of this portion terminates with a male taperedthread 26 of standard pitch, and a central concentric passage 27 extendsthrough the mandrel to provide passage for drilling mud. Continuingupwardly from the lower portion 25 the mandrel is provided with areduced cylindrical section 28 which upon assembly slidably engageswithin the split bearing ring 22. The section 28 is interrupted by threeradially extending cutter blades 29 having tapering end walls 30 and acutting edge 31 which describes a circumference greater than that of thehousing. Extending upwardly from the cutter blades 29 are splines 32which are slidably received in the guide grooves 16 and 18 of thehousing. The mandrel continues with a further cylindrical section 33which is machined for a clearance association with the enlarged bore 13and terminates with a threaded portion 34, and finally with a smallercyindrical end piece 35 to complete the mandrel.

It will be clear that the cutter blades 29 extend through the radialslots 14 and are free to move along the length of the slots. Movement isrestricted by a packer and springassembly which is located at the innerend of the enlarged bore 13. This assembly starting at the innermost endof the bore consists of a sleeve 36 formed with a central passage 37 foralignment with the passage 12. The inner end of the sleeve is tapered asindicated at 38. Seated in the tapered portion of the sleeve is a springholder 39 having a plug portion 41) of lesser diameter than the bore 13to receive and guide one end of a compression spring 41. The springholder has a central passage 42 to form a continuation of the passage37. The packing is mounted over the end piece 35 and consists first of abrass ring 43 which is internally threaded for engagement on thethreaded portion 34 of the mandrel. Next adjacent the ring 43 is a leadring 44 which abuts with a rubber packer sleeve 45. An end sleeve 46 hasa tapered rim 47 which abuts with one end of the second spring holder48. The spring holder 48 has a plug portion 49 for mounting the otherend of the spring 41. It is also provided with a counterbore 50 forsliding engagement over the cylindrical end piece 35 and permittingclearance beyond the end of the end piece such that the several packingelements become constantly under compression by the compression spring.The spring holder also has a central passage 51 to form a continuationof the passage 27 which extends through the mandrel. It will also beappreciated from the drawings that all of the elements in the packer andspring assembly just described have an external diameter equal to thatof the enlarged bore 13 in the housing.

Two steel wiper bands 52 are adapted to slidably engage over thecylindrical surface 9 of the lower portion 8 of the housing so that theymay slide along the surface of the housing and wipe caked materialtherefrom. Bands 52 are received in small slots 53 formed in the endwalls 30 of the cutter blades 29. The bands are assembled one at eachend of the cutter blades.

The embodiment of the invention shown in FIGURES 5 and 6 illustrates inan enlarged scale various modifications of the tool.

Referring to FIGURES 5 and 6, it may be seen that the tool has a housingor sleeve 60 with a longitudinal passageway 62 extending therethrough.Passageway 62 has an enlarged portion 64 at one end to receive a mandrel66. Four helical slots 68 are located about the periphery of housing 60.The lower end of housing 60 is threaded at 70 to receive a nut 72 whichholds a bearing ring 78 in place.

Mandrel 66 is slidably mounted in enlarged passageway 64 and has fourhelical blades 76 mounted thereon. Each of the blades extends throughone of slots 68. The blades are free to slide in the slots but arerestricted in their movement at one end by the end of the slots and atthe other end by the bearing ring 78 mounted in nut 72. Wiper studs 74are mounted on housing 60 adjacent each of slots 68 with one wiper studon each side of each slot. Each of blades 76 is in sliding engagementwith the pair of wiper studs '74 mounted adjacent the slot through whichthe blade extends.

Mandrel 66 has helical splines which slide in helical grooves in thehousing 60 to transmit rotary motion between the housing and themandrel. Except for being helical these splines and grooves aresubstantially the same as those illustrated in FIGURES 2 through 4.

A pair of annular wiper bands 80 and 82 are mounted in slots 84 in theends of blades 76 with one band being mounted on each end of the blades.Alternatively, the wiper bands may be made in curved segments with thesegments extending between adjacent blades. The wiper bands have asliding clearance with housing 60 so that as the blades 76 slide inslots 68, wiper bands 80 and 82 will slide along the surface of housing60.

A packing 88 is mounted on an extension 86 of man drel 66. The packingwhich may be of any conventional type is illustrated here as having twogroups of packing elements urged apart by a spring 92. One group abutsmandrel 66 at the junctions of extension 86 and the other group abuts asnap ring 90 mounted in a seat 91 at the end of extension 86. Mandrel 66has a longitudinal bore 94 which communicates with bore 62 of housing 60for allowing drilling fluids to be passed through the tool. Packing 88permits mandrel 66 to slide in housing 60 while at the same timepermitting drilling fluid to pass through passageways 62 and 94.

The end 95 of mandrel 64 is threaded to receive a tool joint 96 forconnecting one end of the tool to the drill string. Similarly, the toolis connected at its other end to the drill string by threads (not shown)on the end of housing 60.

In use, the tool may be mounted in the drill string with either endextending upwardly. Specifically, the mandrel may be connected to theportion of the drill string leading to the bit and the housing to theportion of the drill string leading out of the drill hole or the housingmay be connected to the portion of the drill string leading to the bitand the mandrel may be connected to the portion of the drill stringextending out of the drill hole. The tool will operate equally well ineither position.

Referring specifically to the embodiment illustrated in FIGURES 1through 4, it will be seen that after the tool has been mounted on thedrill string and is lowered into the drill hole, the weight applied tothe drill string will cause the tool to retract mandrel 24 withinhousing 5. During the drilling operation, drilling fluids are pumpedthrough the drill string and pass through passageways 12 and 13 ofhousing 5 and passageway 27 of mandrel 24.

To clean the tool when materials such as cuttings,

wall cake and drilling fluids collect in a ball about the blades of thetool, the operator simply picks up on the drill string. Assuming thatthe mandrel is connected to the portion of the drill string leading tothe bit and the housing is connected to the portion of the drill stringleading to the surface, this picking up causes housing 5 to slideupwardly of mandrel 24 to the position illustrated in FIGURE 1. As thehousing slides upwardly, grooves 16 slide upwardly along splines 32 andthus rotating of the drill string at the surface of the drill hole willcontinue to rotate the mandrel and hence the drill bit.

The sliding of the housing causes slots 14 to slide upwardly alongblades 29. The movement of the portion of the surface of the housingextending between slots 14 past wiper bands 52 causes balled-up materialon this portion of the housing to be sheared from the housing by wiperbands 52. While two wiper bands 52 are illustrated, it will be apparentthat if desired the upper wiper band could be eliminated since the lowerwiper band cleans the portion of the surface of the housing which isnormally between the blades and very little balling up will occur in theshort period of time during cleaning in which the blades are in thelower ends of the slots.

The material which has been sheared from the tool is carried to thesurface, of the drill hole by the drilling mud which is passing upwardlybetween the walls of the drill hole and the drill string. Once theoperator has picked up on the drill string, he immediately lets it downallowing the normal running weight to once again slide housing 5 downover mandrel 24. During this sliding movement, wiper bands 52 once againshear off any material adhering to the portion of the surface of housing5 between slots 14.

If the tool is inverted in the drill string with mandrel 24 connected tothe portion of the drill string leading to the surface of the drill holeand housing 5 connected to the portion of the drill string leading tothe bit, the picking up and letting down of the drill string will slidethe mandrel up and down in the housing rather than sliding the housingup and down on the mandrel. The wiping action will be similar to thatdescribed above only wiper bands 52 will move along the surface of thehousing, rather than the housing moving beneath the wiper bands.

Thus, it may be seen that the balled-up material may be cleaned from thetool without removing the tool from the drill hole. By picking up on thetool every thirty minutes to two hours, the operator can keep the toolfrom being balled up and eliminate the attendant disadvantages normallyfound in tools not having a selfcleaning feature.

The operation of the embodiment illustrated in FIG- URES 5 and 6 issimilar to the operation of the embodiment described above. Here,however, the blades and slots are helical. Thus if housing 60 isconnected to the portion of the drill string leading to the surface ofthe drill hole and mandrel 66 is connected to the portion of the drillstring leading to the bit, the picking up of the drill string will causehousing 60 to move from the position illustrated in FIGURE 5 to theposition illustrated in FIGURE 6.

The upward movement of the housing causes the helical grooves in housing60 to slide over the helical splines in mandrel 66, thus slightlyrotating mandrel 66 with respect to housing 60 and allowing helicalslots 68 to slide upwardly past helical blades 76 The upward movement ofhousing 60 causes wiper bands 80 and 82 to shear balled-up material fromthe portion of the surface of housing 60 which is between slots 68.Wiper studs 74 provide an additional wiping action by shearing any cakedmaterial from the sides of blades 76 as the wiper studs pass alongblades 76. Similarly, the downward movement of housing 60 accompanyingthe letting down of the tool causes wiper bands 80 and 82 to once againmove across the housing and blades 76 to once again move past wiperstuds 74 shearing any newly collected material from the housing andblades, respectively.

If the tool is inverted in the drill string with mandrel 66 connnectedto the portion of the drill string leading to the surface'and housing 60connected to the portion of the drill string leading to the bit, themandrel will be slid up and down in the housing rather than the housingbeing slid up and down on the mandrel. Thus, the upward movement of themandrel will cause the helical splines and grooves to rotate the housing60 with respect to the mandrel to allow helical blades 76 to slideupwardly in helical slots 68. The wiping action will be similar to thatdescribed above, only the wiper bands 80 and 82 will move along thesurface of the housing, rather than the housing moving beneath the wiperbands and the helical blades will move along wiper studs 74, rather thanthe studs moving along the blades.

Though either of the embodiments may be use-d as reamers, stabilizers orcombination reamers and stabilizers, the helical blades are particularlyuseful when the tool is used as a stabilizer since the blades willcontact a greater area of the wall of the drill hole as the tool movesthrough the hole. This greater area of contact makes the stabilizer moreeffective since it is less likely to be aifected by longitudinalirregularities in the wall of the drill hole.

In summary, the advantages are several. The tool will produce a truegauge hole which is straight and due to longitudinal movement of theblades, balling up of the blades is averted and good circulation ofdrilling fluid is assured. The elimination of the balling-up effectpermits the desired weight to be put on the drilling bit since therewill be no drag caused by the blades. .As a result of these advantages,the drilling rate is increased and the entire drilling string works withmore reliability and precision.

There has been illustrated and described what are considered to bepreferred specific embodiments of the invention. It will be understoodhowever that modifications and variations of this invention will becomereadily apparent to those skilled in the art without departing from thescope of the invention which is defined in the appended claims.

I claim:

1. A selfcleaning drill string tool comprising in combination: a sleevehaving means at one end to connect said sleeve to the drill string, saidsleeve having at least one elongated slot; a mandrel slidably mounted insaid sleeve with one end of said mandrel directed out of said sleeve,said one end of said mandrel having means to connect said mandrel to thedrill string; at least one blade mounted on said mandrel and extendingthrough a portion of an elongated slot in said sleeve and being slidablein the slot; and wiping means mounted on said blade adjacent said sleevewhereby the relative sliding of said blade and the slot of said sleevewill cause said wiper means to wipe caked material therefrom.

2. The tool of claim 1 wherein said slot and said blade are helical.

3. The tool of claim 1 including at least one wiper stud mounted on saidsleeve adjacent said slot whereby relative sliding of said blade and theslot will cause said stud to wipe caked material from said blade.

4. The tool of claim 1 wherein said sleeve has a plurality of slotsspaced about its periphery, and said mandrel has a plurality of bladesextending through said slots.

5. The tool of claim 4 wherein said slots and said blades are helical.

6. The tool of claim 4 including wiper studs mounted on said sleeve oneach side of the slots whereby the relative sliding of said blades andthe slots will cause said studs to wipe caked material from said blades.

7. The tool of claim 4 wherein said wiping means comprises an annularband mounted on said blades and extending around said sleeve.

8. The tool of claim 7 including wiper studs mounted on said sleeve oneach side of said slot whereby the relative sliding of said blades andthe slots cause said studs to wipe caked material from said blades.

9. The tool of claim 7 wherein said blades are elongated and two annularWiper bands are mounted on said blades with one Wiper band being at eachend of said blades.

10. The tool of claim 9 including wiper studs mounted on said sleeve oneach side of the slots whereby the relative sliding of said blades andthe slots will cause said studs to wipe caked material from said blades.

11. The tool of claim 10 wherein the slots are about twice as long assaid blades.

12. The tool of claim 10 wherein said blades and the slots are helical.

13. The tool of claim 12 wherein the slots are about twice as long assaid blades.

14. A self-cleaning drill string tool comprising: a sleeve having meansat one end to connect said sleeve to the drill string, said sleevehaving at least one elongated slot; a mandrel slidably mounted in saidsleeve with one end of said mandrel directed out of said sleeve, saidone end of said mandrel having means to connect said mandrel to thedrill string; at least one blade mounted on said mandrel and extendingthrough a portion of the elongated slot in said sleeve and beingslidable in the slot; and wiping means mounted on said sleeve adjacentsaid slot whereby the relative sliding of said blade and the slot willcause said wiping means to wipe caked material from said blade.

15. The tool of claim 14 wherein the slot and said blade are helical.

16. The tool of claim 14 wherein said sleeve has a plurality of slotsspaced about its periphery, and said mandrel has a plurality of bladesextending through-said slots.

17. The tool of claim 16 wherein the slots and said blades are helical.

18. The tool of claim 16 wherein said wiping means are studs and onestud is mounted on said sleeve on each side of slots whereby therelative sliding of said blades and the slots cause the studs to wipecaked material from said blades.

19. The tool of claim 18 wherein the slots and the blades are helical.

References Cited by the Examiner UNITED STATES PATENTS 1,331,126 2/1920Robichaux -313 1,590,773 6/1926 Moore 175-313 X 2,815,930 12/1957 Storm175-295 2,865,605 12/1958 Chadderdon 175-295 3,051,255 8/1962 Deely175-406 X CHARLES E. OCONNELL, Primary Examiner. N. C. BYERS, AssistantExaminer.

14. A SELF-CLEANING DRILL STRING TOOL COMPRISING: A SLEEVE HAVING MEANSAT ONE END TO CONNECT SAID SLEEVE TO THE DRILL STRING, SAID SLEEVEHAVING AT LEAST ONE ELONGATED SLOT; A MANDREL SLIDABLY MOUNTED IN SAIDSLEEVE WITH ONE END OF SAID MANDREL DIRECTED OUT OF SAID SLEEVE, SAIDONE END OF SAID MANDREL HAVING MEANS TO CONNECT SAID MANDREL TO THEDRILL STRING; AT LEAST ONE BLADE MOUNTED ON SAID MANDREL AND EXTENDINGTHROUGH A PORTION OF THE ELONGATED SLOT IN SAID SLEEVE AND BEINGSLIDABLE IN THE SLOT; AND WIPING MEANS MOUNTED ON SAID SLEEVE ADJACENTSAID SLOT WHEREBY THE RELATIVE SLIDING OF SAID BLADE AND THE SLOT WILLCAUSE SAID WIPING MEANS TO WIPE CAKED MATERIAL FROM SAID BLADE.